1. Field of Invention
The present invention pertains to a word processor and, more particularly, pertains to the display controller for the word processor.
2. Description of the Prior Art
Prior art word processors have five major disadvantages of high front-end cost: numerous, extensive and complex logic boards in the electrical circuit; extensive software requiring complex routines in addition to long periods of time to run, questionable reliability; and complex functional keyboards for a user in operating the word processor requiring considerable knowledge and training.
Prior art word processors have traditionally been high cost and serving the high-end markets such as large corporations and large businesses who could afford such equipment which in the past has usually been considered a luxury. The prior art systems have usually required complex logic circuits, dedicated space and dedicated furniture, all of which added to front-end cost.
Recent prior art word processors have been low cost and are difficult to use in that the keyboard simulates a computer keyboard having little relation to a typewriter keyboard. The CRT screen is similar to a computer terminal. The screen text has no relation to a typed page and typically no margins.
Prior art word processors for the most part contained numerous logic boards, each board having numerous components. The number of logic boards, added to the cost, complexity and reliability of the word processor, and in addition generated considerable heat and noise besides consuming large amounts of power. Numerous logic circuits are susceptible to all of the electrical pitfalls of extensive logic circuits.
Prior art word processors required extensive software having complex routines which require relatively long periods of time to load and run, based on extensive logic circuitry. Complex software results in numerous difficulties to the designers of hardware and results in the vicious software-hardware circle, subsequently yielding a high cost system. Further, prior art machines are locked into specific software thereby not providing for other software packages for disciplines such as accounting, etc.
Prior art word processors have had reliability problems due to extensive hardware logic and extensive software, low level language and custom tools. It has been common for the word processors to cease to operate based on logic failure or to lock up due to a software or hardware-software problem. Such an occurrence is not only frustrating to the user in addition to being costly, but also is non-productive which is a most important consideration.
Prior art keyboards have required considerable manual manipulation in performing such tasks as editing, erasing, underlining, and other related word processing functions. The operator utilized extensive time in performing word processing functions in having to touch numerous keys for implementing a word processing function. The operator after a period of time would suffer from physical fatigue as well as mental fatigue in performing a word processing task or tasks. Some prior art keyboards would not even perform the full range of word processor functions. The prior art keyboards resulted in lost time and motion, and were non-productive and expensive to the end user. Most importantly, the prior art word processor keyboards required considerable operator training.
One other significant prior art problem was the CRT display. Prior art screen displayed green characters on a dark background or white characters on a dark background, both types of displays which also contributed to operator fatigue. The screens over-enhanced the high contrast characters leading to eyestrain in viewing precise characters on such a CRT background. Also, where a white background was displayed on a CRT, the white background was smaller in size than a full sheet of paper such as not displaying the entire length or width of an electronic sheet of paper.
Another significant prior art problem was that prior art word processors required the use of a separate code for many special characters used in foreign languages that are built from standard characters. For example, a first code was required for the letter "e" while a second different code was required for the character "e". The required extra codes required extra memory as well as display time, etc.
Additional prior art problems were the ability to simulate word processor typewriter integrity including a full electronic sheet of paper on a CRT screen with vertical scrolling of the sheet of paper including page breaks between each page as in a real mode of typing. Prior art word processors have failed to initiate a true electronic typewriter. The prior art machines also failed to generate a full sheet of electronic paper such as a standard sheet (81/2".times.11" or A4) including margins on a full size CRT screen. Another problem was adequate display of information for the user to select options or instructions such as for set up, display, typing attributes, or subsequent printing. A further problem was that prior art word processors usually displayed nontyping codes on the screen which were required for use by the operator during information processing functions. Finally, some prior art word processors displayed codes or other modes for processing functions on the screen during typing.
The present invention overcomes the disadvantages of the prior art by providing a word processor which overcomes the disadvantages of the prior art problems and provides a highly efficient system which is simple, reliable and affordable. The system is user oriented, using techniques familiar to a typist and other functions are organized so that a typist can easily access and implement normal typist duties without formal training and assistance from others.